Due to the unique environment in which they are used, aircraft seat structures must meet a number of requirements. For example, such seat structures must satisfy government requirements involving aircraft safety. In addition, such seat structures must meet relatively rigid weight guidelines in order to provide satisfactory economical operation of an airplane in which they are used while, at the same time, occupying a minimum of space and still providing maximum passenger comfort and convenience.
Some of the more comfortable aircraft seats can both “track” and swivel. Tracking a seat is the ability to move a seat linearly, while swiveling allows the seat to rotate about an axis. One problem with some vehicle seats that track and swivel, especially aircraft seats, is that if they have leg rests, these often interfere with the base of the seat when seat is swiveled around. This interference typically damages the upholstery and thus aircraft operators are constantly required to perform maintenance on the seat base to keep the interior of the aircraft looking pristine.
The interference is typically caused by the large seat base size. In the aircraft industry, the seat base is sized to fit a particular aircraft and this dictates the required seat base size, regardless of the actual size of the seat itself. In the prior art, to avoid contact between the seat base and the leg rest, the seat occupant must actively track the seat away from the base as the swiveling motion is accomplished. Without this active participation from the seat occupant, the contact that occurs often damages the seat base covering or even the underlying structure.
Another approach to avoid interference between the leg rest and the seat base is to limit the longitudinal tracking of the seat. This approach maintains the leg rest at a minimum distance from the seat base at all times. The biggest disadvantage to limiting the longitudinal tracking is that it only works for small seat bases. As the required seat base grows, the tracking limitation grows as well, eventually, leading to an unacceptable motion envelope
Thus, there is a need for a seat with a leg rest that can automatically track while swiveling to avoid damage to the seat base covering.